Abstract:
This dataset contains CTD (conductivity, temperature, depth) data obtained from the GEOSCIENCE of the Nella Dan, during Jan - Mar 1982. There are six other cruises which also collected oceanographic data, who are primarily involved with conducting a long term field survey on krill and other zooplankton. 7 CTD casts were taken in the Prydz Bay region, as a supplement to the seismic survey. As a result, the CTD locations were not always ideal for oceanographic purposes.

Quality
Oceanography measurements were taken where possible, which was not always at ideal locations. Therefore coverage of the area is not necessarily complete. This data however, adds to that collected on six other cruises, providing oceanographic data from a wide range of seasons and conditions.

Data collection: A Neil Brown Mark III CTD (conductivity, ... temperature, depth probe #2568) system attached to a rosette water sampler (InterOcean) was used for collecting continuous vertical profiles of conductivity and temperature. Water samples were collect at different depths using the rosette water sampler with 5L Niskin bottles. Measurements were made on the downcast, and water samples collected on the upcast. The water sampling depths were determined depending on the readings made during the downcast. The CTD was lowered at a rate as close to 1 m/sec, and raised between samples at speeds between 1 and 2 m/sec. Conductivity and temperature readings were also made at each water sampling station. 7 CTD stations were taken on an opportunistic basis.

Ship-board processing: Water samples were analysed on board the ship for salinity and oxygen.

Post-ship processing: Data was initially recorded on audio cassettes, but later replayed to produce digital nine-track magnetic tapes by a PDP 11/23. Data tapes were then processed on a VAX 11/750. For each CTD downcast, an uncalibrated, despiked file was generated, using a recursive filter to compensate for sensor mismatch. The data files were used to generate 2 dbar averages for in situ temperature, salinity, sigma-t, specific volumne anomaly and geopotential anomaly. The averages were centred on even, integral depths, and were only calculated when averages contained eight or more valid data points. The temperature and conductivity means were calculated for the interval, and the salinity calculated for the mid point of the pressure interval from the temperature and salinity means. Data processing software was supplied by CSIRO Division of Oceanography. The complete dataset is logically consistent, as seismic data were also obtained at the same sampling sites as the oceanographic data. The cruise track was established before the experiment in order to eliminate bias. The oceanographic sampling was done as a supplement to the seismic survey program, so sampling location and depth were not necessarily selected according to oceanographic related considerations.